LUBBOCK, Texas (AP)  Luis Carlos Montalvan, a decorated Iraq war veteran who became a strong critic of the war and wrote a best-selling book about it, has died in El Paso. He was 43.

Montalvan was found in a hotel room in downtown El Paso late Friday, El Paso police Sgt. Enrique Carrillo said Monday.

The medical examiner’s office has not completed a preliminary autopsy report.

Montalvan served 17 years in the Army, doing two tours in Iraq. He received two Bronze Stars and the Purple Heart.

His service dog, Tuesday, was the subject of Montalvan’s book, which became a New York Times best seller.

Some Army colleagues said Montalvan, who retired from the Army as a captain in 2007, embellished his account of the incident that led to his Purple Heart.

Tuesday is now being cared for by a loving family in the Northeast, according to a statement from Montalvan’s family.

“He was an extremely dedicated activist nationwide for multiple causes, including rights and benefits of veterans and the disabled, as well as the promotion of service dogs,” the statement reads. “His spirit lives on through his family and friends, Tuesday, his writings, and all the people he touched during his years of service to his country and his humanitarian work.”

Montalvan’s book, ” UNTIL TUESDAY: A Wounded Warrior and the Golden Retriever Who Saved Him,” was praised by Sen. Al Franken of Minnesota, made him a leading advocate for wounded veterans and even led to an interview on David Letterman’s show. But several men who served with him told The Associated Press in 2011 that he had exaggerated or fabricated key events from his service abroad. The AP also obtained documents that contradicted Montalvan’s statements about the extent and severity of his injuries.

Montalvan, who earned his bachelor’s degree at the University of Maryland  College Park and a master’s degree from the Columbia University Graduate School of Journalism, declined to speak with the AP at the time, but issued a statement through his lawyer that his book “is a reflection of my experiences in the United States Army (and after) during one of the most controversial military actions since the Vietnam War. Some of the events described in ‘Until Tuesday’ resulted in wounds to myself  both visible and invisible.”

Hachette Book Group, which published his first book and will publish his second, “TUESDAY’S PROMISE: One Veteran, One Dog, and Their Bold Quest to Change Lives,” said in a statement that it was “deeply saddened” at Montalvan’s death.

“With his beloved service dog Tuesday at his side, Luis spent the past decade educating the public about trauma and advocating for veterans and people with disabilities,” the statement reads. “He will be missed greatly and our thoughts and prayers are with his family at this time.”

The organization that united Montalvan with Tuesday has set up a webpage in his honor. Donations can be made at www.ecad1.org/Luis .